Environ Pest Control

What Is The Difference Between Mice And Rats?

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Both rats and mice are elusive creatures that can thrive undetected – spreading disease and damaging property – until their population is too big to be ignored.

But once you realise you have unwelcome pests in your home or business, you need to know what you’re dealing with so you know how to take action.

Luckily, it’s easy to tell the difference between a mice and rat infestation if you know what to look for, which is exactly what this guide will teach you.

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Rats are worse in every way

If you’re not sure whether you have rats or mice, then it’s probably mice. Rats are almost a foot long (not counting their tail) and are less inconspicuous than their tiny cousins: they’re bigger, noisier, greedier and smellier – which means they leave more evidence of all types.


“If it’s rice, it’s mice.” This easy-to-remember rhyme refers to the size and shape of mouse droppings, while rat droppings are much larger at ¼ to ½ an inch.

Mice leave their droppings as they move around and feed, while rats are more likely to do their business in a concentrated area.


Mice only need a hole that size of a ball-point pen to be able to squeeze their bodies through, making it easy for them to travel unnoticed through your home or business.

Rats have a harder time staying undetected as their holes are one to two inches in diameter and can even be gnawed through concrete.

Rats also have a nasty habit of chewing through electrical cables, causing power outages and fires. 25% of electrical fires in the UK are caused by rats.


Their larger size makes rats much noises than mice, as does their need to constantly gnaw in order to wear down their teeth.

Rats also chirp and chatter to communicate. Their language is louder and more varied than the high pitched squeaks of mice, many of which are ultrasonic (outside of the range of human hearing).

Behaviour Differences Between Rats and Mice

Mice don’t need water to survive

Mice are so small that they can get enough moisture from their food, while rats need a reliable water supply to survive and breed.

This means that drains and leaky pipes are strongly related to rat infestations. While mice can happily settle into a home or business, rats often live in drains and journey out to find food so that they have access to both food and water.

Rats are cautious and hard to trap

One of the many attributes of rats that have helped them thrive is their neophobia, fear of new objects or changes in their environment.

This makes them difficult to trap as – unlike mice, which are naturally curious – rats will simply avoid any traps that are put down. To trap a rat, you need to be patient and wait for the neophobia to wear off, which is why we space our rat visits weeks apart.

Rats are usually pushed into homes or businesses

Mice thrive inside our buildings and are small enough to stay hidden, but rats typically only enter our homes or businesses to feed, preferring to nest in sewers or empty structures.

If you have a rat infestation, the first thing we look for is an external influence that pushed them into your premises, such as building works or blocked drains that pushed them out of their home.

Treatment Differences Between Rats and Mice

Poisons shouldn’t be used on rats

Mice have small bodies that can be effectively dried out by professional desiccating poisons (not to be confused with shop-bought poisons which we do not recommend) which prevents any rot or odours coming from the carcass.

Rats, on other hand, are too large for desiccating poisons to be effective, and leave behind a large carcass which not only produces a sickening odour as it rots but also sustains huge populations of maggots and flies – often becoming a worse problem than the rat was.

Drain inspection is essential for preventing rats

Because they often make their homes in drains and travel up into homes or businesses to find food, a drain inspection is standard in our assessment, control and prevention of rat infestations.

Rats are able to hold their breath for seven or more minutes, allowing them to swim through even water-filled drains with ease. We use CCTV drain installations to spot rats as they sneak into your home or business.

There’s no need for drain inspections for mice infestations as this is rarely, if ever, the source of infestation and they prefer to settle within the premises.

5 differences between rats and mice

  1. Mice droppings are the size of a grain of rice, rat droppings are ¼ to ½ an inch.
  2. Mice gnaw on food and hide, rats steal food to store it away.
  3. Mice can squeeze through a hole the size of a ballpoint pen, rat holes are one to two inches wide.
  4. Rats are neophobic and will avoid traps, mice are curious and easily trapped.
  5. Rats need a constant supply of water to survive, mice can get by on the moisture in food.

Rats or Mice? Call Environ Now

Whatever rodent is bothering your business or haunting your home, call Environ now or request your call back to book an inspection from our BPCA-certified pest control team.

Here are some other helpful articles about Rats

Why Do I Have Rats in My Garden?

Read Ricky’s tips for how to spot and prevent a rat infestation in your garden, including what they eat and drink, where they nest and the evidence they leave.

Need a Jack Russell Rat Catcher?

Do you need to kill a rat? Then leave it to the experts: our rat-catching Jack Russell dogs. They will find the rat that was keeping you up all night and kill it in seconds.

I Just Saw a Rat, What Do I Do?

Seen a rat? DON’T WAIT. Call NOW to request our emergency rat response service – a team of our best pest control experts and our trained rat catching Jack Russell.

Do Rat Traps and Poisons Work?

Find out the best way to use rat traps, and why poisons should never be used. Maggots and flies feeding on a dead rat are often a bigger issue than the rat was.

Rats Crawling Up Your Drains? Get Drain Rat Proofing and CCTV Inspection from Environ

Stop rats crawling up through your drains with our drain rat proofing service and CCTV rat inspection. If you don’t, they’ll keep coming back, again and again.

Rat Control London - Get Effective, Long-Lasting Rat Extermination from a Family-Run London Business

Get rid of rats for good with Environ, London’s most trusted rat exterminators, used by beloved brands, Michelin-starred restaurants and countless London homes.

How Can I Get Rats Out of My House?

Rats spread disease and damage your property. Don’t let them get comfortable. Click here to find out how rats get into your home and how you can get rid of them

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